SPM Bulletin 21

Contents: 1. Editor's note; 2. Personal impressions from the SPM07 meeting; 3. Research announcements; 3.1. Coloring ordinals by reals; 3.2. Long Borel Hierarchies; 3.3. Rothberger's property in finite powers; 3.4. Special subsets of the reals and tree forcing notions; 3.5. All automorphisms of the Calkin algebra are inner; 3.6. Continuous selections and sigma-spaces; 3.7. On the closure of the diagonal of a T1-space; 3.8. Splitting families and Noetherian type; 3.9. Even more simple cardinal invariants; 3.10. A classification of CO spaces which are continuous images of compact ordered spaces; 4. Problem of the Issue